My brother and I am converting an '86 GL into a 2.2 liter from a '96 Legacy with the harness from a '91 Legacy, we are disassembeling the wiring harness and we ran into a discrepancy with the alt connector, the harness is a circular 3 wire connector and the engine's alt from a '96 is a square connector with two progs. Which of the two wires from the harness do we need to splice into the alt without the connector?


~Mike

You're going to run into a lot more issues with wiring. The 96 legacy is OBD2. The 91 legacy is OBD1. I'd strongly suggest getting the wiring harness from the 96-99 vintage legacies (95 had its own weird harness, so I'd stay away from it)

As for the alternator, One wire is the light, one is sense, and on one is ignition. The big fat one on the 91 harness is the ignition wire. You don't need it. The older alternators needed an ignition signal to turn the alternator on. The newer alternators turn on once rpm is above a certain point.

These scans will tell you which one is light and which ones is sense
http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/alternator1.jpg
http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/alternator2.jpg

He's taking a complete 91 legacy 2.2 harness and running a 96 engine. He's not trying to use a 96 ecm with a 91 harness.
You can cut the plug on the alternator and soldier the old wires into place and it will work just fine. You'll want to look in a factory service manual and figure out which wire is what though. I did this for my new wrx engine.
I think i might still have the connector for the 96 alternator around somewhere if you want it....
Good luck
B